Electric signal transmission line

Abstract

An electric signal transmission line includes a signal electrode portion, a ground electrode portion and a dielectric portion formed on a semiconductor substrate. The signal electrode portion has a metal electrode through which an electric signals flows. The ground electrode portion has a grounded metal electrode. The metal electrode of the signal electrode portion and the metal electrode of the ground electrode portion are connected with a semiconductor PN junction. The dielectric portion is formed by using a dielectric to cover a region between the metal electrode of the signal electrode portion and the metal electrode of the ground electrode portion through which a line of electric force runs and is a region in which energy of transmitted electric signals exist.

1. An electric signal transmission line, comprising:
 a semiconductor substrate; 
 a signal electrode portion formed over the semiconductor substrate and including a lower conductive semiconductor, an upper conductive semiconductor formed on the lower conductive semiconductor, having a polarity different from that of the lower conductive semiconductor and forming a PN junction in conjunction with the lower conductive semiconductor, and a metal electrode which is formed on the upper conductive semiconductor and through which an electric signal flows; 
 two ground electrode portions provided respectively at opposite sides of the signal electrode portion over the semiconductor substrate and each including a conductive semiconductor having a polarity identical with that of the lower conductive semiconductor and a metal electrode formed on the conductive semiconductor and grounded; 
 a first conductive semiconductor having a polarity identical with that of the conductive semiconductor of the two ground electrode portions, connecting the signal electrode portion and two ground electrode portions to each other and to the semiconductor substrate; 
 a dielectric portion having a dielectric that covers a region between the metal electrode of the signal electrode portion and the metal electrodes of the two ground electrode portions, through which a line of electric force runs and which is a region in which energy of transmitted electric signals exists. 
 
   
   
     2. An electric signal transmission line according to  claim 1 , further comprising a space of an appropriate depth that is formed by etching between the metal electrode of the signal electrode portion and the metal electrodes of the ground electrode portion, that separates an exposed surface of the first conductive semiconductor from the region through which the line of electric force runs, and that is filled with a dielectric to form the dielectric portion that also covers the metal electrode of the signal electrode portion and the metal electrodes of the ground electrode portions. 
   
   
     3. An electric signal transmission line according to  claims 1  or  2 , wherein the dielectric used to form the dielectric portion is an organic material having a dielectric constant of not more than 3. 
   
   
     4. An electric signal transmission line according to  claim 3 , wherein the dielectric used to form the dielectric portion is formed of polyimide. 
   
   
     5. An electric signal transmission line according to  claim 1 , wherein the lower conductive semiconductor is more highly doped than the first conductive semiconductor. 
   
   
     6. An electric signal transmission line according to  claim 1 , wherein the conductive semiconductor is formed on and in direct contact with a upper surface of the first conductive semiconductor and a lower surface of the first conductive semiconductor is in direct contact with the semiconductor substrate.